Full Mirror Glaze Galaxy Cake recipe with colorful galaxy cake pop planets, a galaxy cake, a galaxy vanilla buttercream, and a galaxy mirror glaze. Outside a shiny and colorful galaxy mirror glaze and inside a galaxy cake with four different planets.
Microwave butter for about 15-20 seconds until very soft and a bit melted. Set aside.
Preheat oven to 350°F / 175°C.
With a handheld or stand mixer fitted with a whisk or paddle attachment, mix eggs on medium-high speed until combined for about 1 minute. Add sugar and mix until light and creamy for about 2-3 minutes. Add butter and mix until creamy. In the end, add flour, baking powder, and salt and mix until fully combined and smooth.
If you want to make the same planets like me, separate batter in 6 bowls and color with navy blue, purple, green, Aztec blue (teal tone), yellow, red, and white. Use gel or paste food coloring. Depending on your food coloring brand, add a few drops to your batter until you reach the desired color.
If you want to use more of one color and less of another, consider the required amount of batter per color while separating into bowls. I added to every portion a bit of white to lighten up the colors.
Use a 20 cake pop mold. Spoon red and yellow batter into a few mold for the sun (the side of the mold without the holes). Blue and green (with a bit of white if desired) for the Earth, teal with a bit of white for Uranus, and purple with a bit of white for Neptune. Fill until level with a very slightly heaping and draw a few swirls with a skewer. Place the second side of the cake pop mold on top (the one with the hole) and close tightly.
Bake for about 18-20 minutes. I baked mine for 20 minutes. Let cool in the mold until you are done with the cake batter. Set aside.
Line two 8-inch baking pans with parchment paper by cutting 8-inch circles for the bottom and about 2-3 inch wide strips for the sides. Use very less baking spray underneath the paper that it sticks to the pan for easier filling.
In a small bowl, whisk milk and egg whites until combined. Set aside.
In another small bowl combine flour, baking powder, and salt and stir to combine. Set aside.
With a handheld or stand mixer fitted with a whisk or paddle attachment mix butter and sugar on medium speed until creamy and combined for about 1-2 minutes. Add vanilla* and mix until combined. Mixing on low speed, alternately add dry and wet mixtures, beginning and ending with dry ingredients. I added the dry ingredients in 3 batches and the wet ingredients in 2. Mix until smooth and combined.
I used 4 colors for the galaxy cake batter. Black, white, pink, and Aztec blue (teal tone). Divide batter into 2 big and 2 small bowls. Add black food coloring and white food coloring in the two big bowls and pink and a bit of Aztec blue in the two small bowls. Add white if you want to lighten up the colors.
Spoon about 1/4 of the colored batter alternately in the two pans equally until the bottom is covered. Gently draw a pattern. Be careful that you don't mix up the colors. Place 10 cake pops planets in each pan. Spoon remaining batter on top of the planets.
Bake for about 27-30 minutes until a toothpick centered in the middle comes out clean (don't pick inside a cake pop). Let cool in pans for about 10 minutes then transfer to a wire rack to cool completely.
Mix butter with a whisk attachment on medium speed until creamy for about 2 minutes. Add 1 cup sugar at the time and mix on low speed until combined. Add salt and mix to combine. Mix in vanilla* and milk until smooth and fully incorporated. Divide buttercream into 4 bowls. I used black, white, blue, and pink. Add white to lighten up the colors if desired. Spoon the colored buttercream alternately into a piping bag.
Place bottom cake layer with a cake board underneath on a turner. Pipe a thin layer of buttercream on top. Even with a big offset spatula by placing the edge of the spatula on top of the cream horizontally and spin the cake around. Place the second cake layer on top. Pipe remaining buttercream on top and the sides until the cake is fully covered. Level the top with the spatula like you did with the bottom cake layer until buttercream is smooth and even.
To level the buttercream on the sides, plant the spatula next to one side uprightly and spin the cake around. Take care that you keep the same angle while spinning the cake around. Smooth the edges by leveling the top again and push frosting very slightly and carefully to the edges. Then level the edges on the sides again and repeat until edges are smoothed.
Freeze cake with the board underneath for about 1 hour that the buttercream is very firm and doesn't melt away while glazing.
Add ¾ cup of water and gelatin in a small bowl and stir to combine. Let bloom for about 10 minutes. It needs to be firm to touch.
Place chopped couverture in a big bowl and set aside.
In a small saucepan bring sugar, 3/8 cup water, and corn syrup over medium heat to a boil and simmer for about 2-3 minutes. Remove from stove and stir in bloomed gelatin and condensed milk until combined. Pour over couverture, cover with a towel and let stand for about 2 minutes.
Mix with a handheld emersion blender until smooth, and no lumps remain. Strain and separate mirror glaze in 5 bowls. Two big ones, and 3 smaller ones. Add Aztec blue and navy blue in a 3:1 ratio in one big bowl. Add black and navy blue in equal amounts to the second big bowl. In the 3 small bowls, add purple, pink, and Aztec blue (teal tone). Add white to brighten up the colors if needed.
Line a cookie or baking sheet with parchment paper. Place a vase upside down in the middle. Remove cake from the freezer and place on top of the vase.
The mirror glaze needs to be 90°F / 32°C while glazing that it is not too thin and not too thick. Use a candy thermometer. When your glaze is too hot, let it stand until it cools down a bit. This will go very fast. Otherwise, the glaze doesn’t stick to your cake and is too runny. When the glaze is too cold, it is too sticky, and you can’t pour it over your cake. In this case, warm it up in the microwave for a few seconds.
Pour the blue from the first big bowl into the very dark space blue in the second big bowl. Give it a few gentle swirls and draw a pattern. Don't mix up the colors. Pour over cake beginning on the top and then let drip over the sides until the cake is fully glazed. Drip with a spoon a few lines of teal, purple, and pink on top. Go with the lines of the light and dark blue pattern.
Brush with a big offset spatula over the top of the cake to smooth the colors. Sprinkle a bit of black pearl dust and white food coloring on top of the cake with a brush.
Let dry for about 1/2 hour then transfer to the fridge and chill for 2 hours. Cut cake with a very warm knife (warm with hot water then dry) for best cutting results. Store leftovers in an airtight container in the fridge up to 3 days.
*First, cut off the straight end of the vanilla bean. Then place the tip of your sharp knife below the curled end and cut the vanilla bean through the middle of the bean lengthwise. Although you don't need to cut it all the way through, it's ok when you do so. Then open the vanilla bean and scrape out the flavorful seeds with the back of your knife. Just use the seeds.